Electric current grounding device



Nov. 7, 1933. J. s. BELTZ 1,933,651

ELECTRIC CURRENT GROUNDING DEVICE 5 Filed April 3, 1929 2 Sheets-Sheet l ywnv-sssn Ff w. WM.- W

NOV. 7, 1933. J, BELTZ 1,933,651

ELECTRIC CURRENT GROUNDING DEVICE Filed April 3, 1929 2 Sheets-Sheet 2 Fig. 3

WI M555 1 Patente d Nov. 7, 1933 PATENT OFFICE ELECTRIC CURRENT GROUNDI NG DEVICE John S. Beltz, Columbus, Ohio, assignor to The Jeffrey Manufacturing Company, Ohio, a corporation of Ohio Columbus,

Application April 3, 1929 Serial No. 352,282

8 Claims. (arias-'49) This invention relates to new and useful improvements in electrical current grounding devices of the type particularly applicable to railway vehicles.-

V 5 It is a primary object of this invention to provide an electric contactdevice which will shunt or by pass the negative or ground currents of an electric circuit around anti-friction bearings normally in the path of suchground currentslin order to prevent a passage of the same through such anti-friction bearings. When current is permitted to pass through such anti-friction bearings which'are very slightly worn, arcing necessarily takes place and the anti-friction rollers, balls or the like as well as other parts of the bearing become pitted and destroy, all

smoothness'of operation of the bearings.

Another object of the, invention is to provide a device of the above character which is of simple and durable construction andwhich can be readily and inexpensively installed without interference with other parts of the apparatus with which it is associated,

A still further object of the inventionis to provide such devices with automatic wear compensating instrumentalities .to maintainefiicient electrical connections between the parts with which it is associated c Other objects and advantages of the invention will become apparent during'the course of the following description.

In the accompanying drawings forming a part of the application and wherein like numerals are employed to designate like parts throughoutthe several views, 7

Figure 1 is a side elevation of Figure 2 is an end elevation of an electric motor for driving a, locomotive, and illustrated with parts broken away to reveal the invention, and l l Figure 3 is a horizontal sectional view taken on the line 3-3 of Figure 2 illustrating a portion of the axle shaft upon which the traction wheels of the locomotive are mounted.

Referring now more particularly to the drawings, I have illustrated a locomotive of the well known type especially adapted for use in coal and other mines, which is equipped with the devices of my invention. As here illustrated and as more particularly described in the pending application of Frederick C. Coseo for Axle journal bearings, Serial No; 350,366, filed March v an industrial electric locomotive especially adapted for use in 27, 1929, the numeral 1 designates the side frames of a locomotive, which frames are preferably formed of rolled steel slabs and which are joined together by suitable end frames 2 to form a rigid hollow rectilinear. frame withinso which is mounted the operatmg jparts of the locomotive. The locomotive-s-here-illustrated is equipped with suitable electricniotors. of the type 7 described in the pendingapplication of I Nils D. Levin, Serial No, 549,765, filed July 9, e5 1331 one of which motors isdesignated by the] letter M, which is furnished electric current through a suitable trolley pole 4 andliscontrolled by the electric controller. -5 positioned convenient to the hand of the operator in a 7 manner which is well understood in the art. It is to be understood, however, that any other suitable power devices maybe: substituted for the electric equipment here illustrated, since these devices form no part of the present lnven-c "tion. The locomotive above described is mounted upon traction wheels 6 adapted to rest upon and travel along the rails .7 of a suitable track, and thesewheels are attached to axles 8, which are driven by a spur gearll keyed to the axle g0 meshing with apinion 10 carried by the armature shaft 11 of the motor M, whereby the locomotive may be propelled along the trackway.

The spur gear 9 hasfl-itshub mounted by an anti-friction bearing lzm of vany suitable type 5 housed within a cup extension m fprmed upon a suspension bearing housing or sleeve] 14in which the axle. shafft8 is mountedandspacedv there from as clearlyshown in Figures 2 and 3, The other end of this suspension bearing housing is formed with a second cup extension ll-lwhlch receives a roller bearing 12 forming a bearing for the axle shaft -The ends of this axle shaft are mounted in roller bearings in axleboxes' imovable vertically as fully disclosed inthe copending application of Nils D. Levin for-Motor suspensions, Serial No; 350,635, filed March 28, 1929 of which the above mentioned Levin application $erial No. 549,765 is a division.

The suspension bearing housing 14 forms a de- 1 tachable part of the field frame of the motor held in spaced relation around the axle 8 by means of bolts 15, as best seen in Figure 2. Ordinarily, the ground or negative current passes from the extension bearing housing through the roller bearings 12, into the axle shaft 8 and is thus grounded through the wheels of the locomotive andrails of the trackway. I propose to alter the normal path of the negative current and shunt it directly through the axle shaft to prevent its llil passage through the anti-friction bearings and thereby prevent the detrimental effects of arcing in worn bearings. This object may be accomplished in several ways of offering a path of least resistance to the ground or negative current whereby it will not seek to pass to the ground by way of the anti-friction bearings and one of these ways is to establish a highly conductive contact between the extension bearing housing 14 and the axle shaft 8. Instead of grounding the current through the traction wheels, it may be returned to the source by a conductor leading from such a contact device or field frame back to the generator.

In the present illustration, the preferred type of contact device between the suspension bearing housing 14 and the axle shaft 8 consists of a cap 16 of bronze or any other suitable conductive material having its open end exteriorly screw threaded to be screwed into a threaded aperture in the extension bearing housing 14. This cap is provided with a polygonal socket or depression 17 in which a wrench may be inserted and which provides the interior of the cap with a concentric inwardlyextending boss 18 to the inner surface of which may be secured, by any suitable means, an insulating washer 19. Positioned within the cap or plug 16 and having a snug sliding fit therein, is an element 20 of bronze or any other suitable conductive material, the fit between these parts being sufficient to establish a proper electrical connection between the two. As best seen in Figure 2, the outer end of the element 20 which projects beyond the cap, is provided with an arcuate bearing and contact surface 21 for wiping engagement with the axle shaft 8. This bear ing surface is constantly pressed into firm contact with the axle shaft by means ofa coiled spring 22, one end of which abuts the insulating washer 19, while the other end abuts the cupshaped element 20 and surrounds an inwardly extending hollow stud 23 formed on the element 20. Thus, it will be seen that a. highly conductive contact is established between the axle shaft 8 and the extension bearing housing 14, so that the ground current'will be induced to travel directly from the extension bearing housing to the axle shaft and will thereby be prevented from passing through the anti-friction bearings 12 to such an extent as to cause pitting of the rollers.

It is to be understood that various changes in the construction and arrangement of parts may be resorted to without departing from the spirit of the invention and the scope of the appended claims.

What I claim is:

1. In a machine of the class described, the combination of an electrical circuit including a conductor frame, a shaft mounted therein, an anti-friction bearing between said shaft and frame, and a conductor forming a ground circuit connection between said frame and shaft and engaging the shaft between its end to prevent the passage of current through said bearing.

2. In a machine of the class described, the combination of an electrical circuit including a conductor frame, a shaft mounted therein, an antifriction bearing forming a conductor connection between said shaft and frame, and a conductor forming a ground circuit connection between said frame and shaft and engaging the shaft between its ends to form a path of less resistance than through said bearing to prevent the passage of current through said bearing.

3. In a machine of the class described, the combination of an electrical circuit including a conductor frame, a shaft mounted therein, a roller bearing forming a conductor connection between said shaft and frame, and a conductor forming a ground circuit connection between said frame and shaft and engaging the shaft between its ends to be arranged in the path of least resistance to said current to prevent the passage of current through said roller bearing.

4. In a machine of the class described, the combination of an electrical circuit including a conductor frame, a shaft mounted therein, an antifriction bearing between said shaft and frame, and a yielding conducting member carried by said frame and engaging said shaft between its ends to form a path of lesser resistance to the passage of electric current than through said anti-friction bearing to prevent the passage of current through said anti-friction bearing.

5. In a machine of the class described, the combination of an electrical circuit including a conductor frame, a shaft mounted therein, an anti-friction bearing between said shaft and frame at one end of said shaft, a contact member carried by said frame between the ends of said shaft, a spring to force said contact against said shaft, and means to prevent currents passing through the spring.

6. In an electric locomotive having a circuit grounded through the axle and wheels thereof, an axle housing through which current passes to said axle, anti-friction bearings between said housing and axle at the ends thereof, and a conductor forming a ground circuit connection be tween saidhousing and axle at a point intermediate the ends of said axle to present a path of less resistance to the grounding current than is offered to the current through said bearings.

7. An electrical contactor comprising two telescoped conductive tubular members having closed outer ends, and a compression spring within said members and acting to expand the same, one of said ends having an inner lug extending within the spring to position the same.

8. An electrical contactor comprising two telescoped conductive tubular members having closed outer ends, a compression spring within said members and acting to expand the same, one of said ends having an inner lug extending within the spring to position the same, and an insulating washer between the other end and the spring.

JOHN S. BELTZ. 

